How the CVE Works:
CVE-2025-23137 is a NULL pointer dereference vulnerability in the Linux kernel’s `amd-pstate` CPU frequency scaling driver. The flaw occurs in the `amd_pstate_update()` function, which fails to validate the `policy` pointer before dereferencing it. If a malicious or buggy process triggers this function with a NULL policy, the kernel will attempt to access invalid memory, leading to a system crash (kernel panic) or potential local privilege escalation. This vulnerability primarily affects systems using AMD CPUs with the `amd-pstate` driver enabled.
DailyCVE Form:
Platform: Linux Kernel
Version: Pre-5.15.137 (patched in later versions)
Vulnerability: NULL Pointer Dereference
Severity: Medium
Date: 04/16/2025
What Undercode Say:
Exploitation:
- Trigger Condition: A local attacker could exploit this by forcing the `amd_pstate_update()` function to execute with a NULL `policy` pointer.
2. PoC Code Snippet:
include <stdio.h>
include <unistd.h>
include <sys/ioctl.h>
int main() {
int fd = open("/dev/cpu_control", O_RDWR);
ioctl(fd, MALICIOUS_IOCTL_CMD, NULL); // Hypothetical trigger
close(fd);
return 0;
}
3. Debugging: Use `dmesg` to check kernel logs for NULL pointer crashes:
dmesg | grep "BUG: unable to handle kernel NULL pointer"
Mitigation:
- Patch: Update to a kernel version with the fix (post-5.15.137).
2. Workaround: Disable `amd-pstate` if unused:
echo "disable" > /sys/devices/system/cpu/amd-pstate/status
3. Kernel Config: Recompile kernel without `CONFIG_X86_AMD_PSTATE`.
Detection:
- Scanning: Use `grep` to check for vulnerable code:
grep -r "amd_pstate_update" /usr/src/linux/drivers/cpufreq/
- Static Analysis: Tools like `Coccinelle` can detect NULL derefs:
spatch --sp-file null_check.cocci --dir drivers/cpufreq/
References:
- Kernel Git Commit: [Link to patch]
- CVE Details: https://nvd.nist.gov/vuln/detail/CVE-2025-23137
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
